Electric pole-changer.



PATENTED MAY 24, 1904.

0. E. SGRIBNBR.

ELECTRIC POLE CHANGER.

APPLIOATION FILED SEPT. 16, 1902.

2 SHEETSSHEET 1.-

N0 MODEL.

Wi/neeqes:

No. 760,574. v PATENTED MAY 24, 1904. G. E.-SGRIBNER.

ELECTRIC POLE CHANGER. APPLICATION FILED SEPT. 15, 1902;

N0 MODEL. 2 SHEETS-SHEET 2.

MVen/or:

Char/a5. A. Jav'ner.

UNITED STATES- iiatented May 24,1904.

PATENT OFFICE.

ELECTRIC COMPANY, ILLINOIS.

ELECTRIC POLE-CHANGER.

SPECIFICATION formingpart of Letters PatentNo. 760,574, dated May 24, 1904. i

- Application filed September15,l902. Serial N01 123,403. immoral.)

To all whom it may concern.-

Be it known that I, CHARLEs E. SCRIBNER, a citizen of the United States, residing at J ericho, in the county of Chittenden and State of Vermont, have invented a certain new and useful Improvement in Electric Pole-Changers, of which the following is a full, clear, concise, and exact description.

My invention relates to pole-changers and their circuits; and its primary object is to obtain an efficient ringing-current at small ex-' pense. g

The invention is especially applicable for use in moderate-size telephone-exchanges in which the transmitter-battery is provided at the different stations in contradistinction to those systems in which said battery-supply is centralized. My improvements are such,

however, that their introduction, I believe, may result in the extension of the use of polechangers into quite large exchanges.

My invention contemplates the use of a poleehanger 1n connection with a signaling-bat- .tery, the battery having one pole thereof con nected, through a condenser or resistance, to

the vibrating or oscillating contact arm, other branches from said pole being connected to the other and alternate contacts of the pole-changer in such a manner that when current is sent to line the resistance will be included in the circuit at the time the other contacts or alternate connections are broken,

thus preventing sparks which would otherwise result from' the extracurrent due to selfinduction in such circuits.

rent of telephone-lines, since its inductive effect upon adjacent lines is minimized thereby.

figures.

It is, moreover, of advantage to thus smooth the signaling-cur resistance p of, say, five thousand ohms being Fig. 3 is a view of the same, showing the contact-arm moved to itsextreme right position. Fig. 4 shows the same in the position which it assumes when the vibrating arm or cHIoAeo, ILLINOIS, A CORPORATION. 0E.

moving to the left, as indicated by the arrow, has parted from the spring to the right and is just closing upon the spring to the left.

Fig. 5 is a view of'the same upon line 5 5 of,

Fig. 3.' Fig/(Sis a diagram illustrativeof the pole-changer as used in a telephone system fordirecting the signaling-battery over the line, and Fig. 7 is a modification or alternate arrangement which consists in substituting'a condenser for the resistance.

Like parts are indicated by similar characters of reference throughout the different The pole-changer proper, as shown in Figs. 1 to 5, consists of the vibrating contact arm or lever a, the pair of contact-springs Z) 0 .on

one side of said'arm,.and the corresponding pair of contact-springs d e on the other side tween springs b d, upon which said springs b d are'alternately closed, and the insulatingof said arm, with the contact f interposed bestud g, pivotally or mo vably mounted between said'springs, which stud when pressed the other to move the same.

.75 upon by one of said springs is forced against I In Fig.6 the telephone-line is shown pro I vided with two stations A B, at eachof which is provided the usual bell, generator,telephone, transmitter, induction-coil, and switch, The

line extends in two branches 1 2 toj thecentral, oflice,where are provided'the usual line-annunciator h and spring-jack switch 70. The f;

operator is provided with'p'lugs and calling-. keys, as indicated at Z m n." ,ITlie pole-changer is connected with the battery 0 as shown, the.

same pole of the battery, as shown by wire is branched to the 'contacts c e of the pole} 4 changer.

by wire 4: with the binding post which sup- The other pole of the batteryin I this instance the negative poleis connected I ports the contact f, which contact f is interposed between the springsb (Z. The Stud 9 I have already described as serving as a medium by which pressure of either'one of the springs Z (Z may be transferred to the other to move the same.

In Fig. 71have shown a battery 0 connected with the pole-ehanger,as in Fig. 6, a condenser q of, say, two microfarads being used in place of the resistance of said Fig. 6.

Assume that the operator at the central office desires to signal the subscriber A. She will insert plug Z in spring-jack Z". and by means of signal-key or connect the battery 0, through the pole-changer,with limb 1 of the telephoneline, which limb leads through the bell at said station A to ground. The current transmitted will be sent in alternations. The arm a, it will be assumed, is started when the key m is operated. Assume that said arm is vibrated, as illustrated in Fig. 1, by an electromagnet or any other suitable means, and we will follow the movements of said arm to the right and to the left in its vibrations. The arm will first close on contact Z and moving on carry said arm 6 into contact with the left and outer spring 0. This position is illustrated in Fig. 3, at which time it will be observed that the positive pole of the battery is connected directly by wire 8 to spring 0, and hence to spring Z, and also at the same time there is a connection from the same pole of the battery through a condenser or resistance to arm a and from the right contact of said arm a to said spring Zthat is to say, the condenser or resistance is in a shunt of the circuit connection through wire 3. The arm having completed its excursion to the right returns toward the left. First spring 5 moves away from spring 0, and coming against the stud g spring (Z is started in its movement toward the left, being separated from contactf, and then spring?) comes against said contact 7", as shown in Fig. 4E, and the arm a, continuing its stroke, carries spring (Z into contact with the outer left spring 0. The arm returning to the right again will permit spring (Z by its own tension to separate from spring 0. At the moment the circuit is broken by the separation of springs (Z c or by the separation of springs Z) cit should be observed that there is a shunt around the said contact-springs through resistance, which may be in the form of a usual resistance-coil of, say, five thousand ohms, or through acondenser of, say, two microfarads, so that there will be no spark or burning at the contacts that are thus shunted.

WVhen one of the keysas, for example, key m-is operated, the current sent over one of the limbs of the circuit in this instance limb 1willin the first instancethat is,when contact a touches spring Zpass through the resistance or condenser 9 or q, and immediately thereafter as the spring 6 touches spring 0 the final impulse of the battery will be thrown on the circuit. Now when the oscillating or moving contact-arm a changes its direction of motion, permitting springs Z) c to separate, the

break between the contacts Z) cwillbebridged or shunted by the resistance or condenser, so there will be no harmful spark developed due to the self-induction of the circuit 1, which includes the signal-bell or annunciator at station A. The same is true as to the operation of springs (Z and e.

I am thus enabled to provide an alternating current for operating signal-bells and annunciators by the use of battery-current and at the same time avoid sparking at the polechanger as the contacts are alternated, the tendency to such sparking being especially pronounced by reason of the fact that in such circuits the signal-receiving device is necessarily of considerable inductance.

From the foregoing description it appears that in my pole-changer the break made on the separation of contacts 7) 0 and (Z (1 will be bridged only at the very moment of their separation, which is the instant at which spark would be liable to be developed. Thus the resistance or condenser is included in the battery-circuit only at the precise instant or instances when needed to perform its function of preventing sparking and at other times is disconnected, so that there is no wasteful flow of current through the same.

Having thus described my invention,1 claim as new, and desire to secure by Letters Patent, the following:

1. The combination with a circuit containing a signal-receiving device of considerable inductance, of a battery and a pole-changer operating to convert the direct current from the battery into alternating current to actuate the signal-receiving device, said polechanger comprising switch-springs for connecting the two poles of the battery alternately with the two sides of the signal-circuit, a contact-lever and means for oscillating the same to operate said switch-springs, and a circuit including a spark-preventing device controlled by said contact-lever and momentarily connected in shunt about the switch-springs when the same are operated to break circuit, whereby alternating current from the battery is directed over the circuit to operate the signalreceiving device while sparking is prevented.

2. The combination with an electromagnetic signal device adapted to be operated by impulses of current, of a circuittherefor including a source of constant direct current, a switch operating to intermittently make and break the said circuit, whereby impulses of current are produced to actuate said signal device, a conductor adapted to shunt said switch, a spark-preventing device included therein, and a key controlling said shunt-conductor and cooperating with the switch to close the shunt momentarily while the switch operates to break circuit, whereby the spark at break is suppressed.

3. The combination with an electromagnetic signal device adapted to be operated by alter- Hating current, of an actuating-circuit therefor, extending to two switch-terminals of a pole-changer, a source of direct current, other switch-terminals of said pole-changer connected to the two poles of said source of current, means operating to bring the first-mentioned switch-terminals alternately into connection With the tWo poles of the source of current at the switch-terminals thereof, to cause current impulses of alternating direction to flow through the signal device, alocal circuit of the polechanger including a condenser, and a switch operated by the aforesaid means to momentarily complete said localcircuit during the break in the shunt of that portion of the ac- I5 tuating-circuit first broken at the switch-terminals of the pole-changer, whereby the spark Q at break caused by inductance in the circuit is suppressed.

In Witness whereof I hereunto subscribe my 20 name this 23d day of July, A. D. 1902.

CHARLES E. SCRIBNER. 

